WO2016121467A1

WO2016121467A1 - Sound-absorbing material and wiring harness with sound-absorbing material

Info

Publication number: WO2016121467A1
Application number: PCT/JP2016/050586
Authority: WO
Inventors: 高田　裕
Original assignee: 株式会社オートネットワーク技術研究所; 住友電装株式会社; 住友電気工業株式会社
Priority date: 2015-01-30
Filing date: 2016-01-09
Publication date: 2016-08-04
Also published as: JP6507681B2; US10618251B2; CN107851430B; JP2016142830A; CN107851430A; US20180015689A1

Abstract

　Provided are: a sound-absorbing material obtained by laminating nonwoven cloth, said sound-absorbing material being provided with a structure which maintains sound-absorption function while imparting flame retardancy, even if said nonwoven cloth is made from flammable fibers; and a wiring harness with sound-absorbing material, obtained by integrating said sound-absorbing material with a wiring harness.　This problem is addressed by: a sound-absorbing material obtained by laminating a substrate made from a nonwoven cloth and a skin material made from a nonwoven cloth having a thickness less than that of the substrate, characterized in that a flame retardant material made from a nonwoven cloth having a higher density than the substrate and the skin material is positioned between the substrate and the skin material; and a wiring harness with sound-absorbing material characterized in that the sound-absorbing material and the wiring harness are integrated by covering at least part of the wiring harness in the axial direction with the sound-absorbing material.

Description

Sound absorbing material and wire harness with sound absorbing material

The present invention relates to a sound absorbing material using a nonwoven fabric, and a wire harness with a sound absorbing material in which the sound absorbing material and a wire harness are integrated.

Conventionally, for the purpose of improving the quietness of the interior of a car, a sound insulation material made of glass wool, rock wool, porous ceramic, urethane foam, waste cotton, or the like is provided in the vicinity of a device that generates noise in the vehicle. A sound absorbing material was provided. However, from the viewpoints of workability, impact on human body, recyclability, environmental load, and weight reduction of sound insulation materials and sound absorption materials, nonwoven fabrics are now widely used for these sound insulation materials and sound absorption materials. . Patent Document 1 listed below discloses a sound-absorbing material made of a nonwoven fabric laminate that includes ultrafine fibers in part.

In recent years, high performance and high functionality have been rapidly promoted mainly in automobiles and electrical appliances. In order to control various electronic devices included in these automobiles and electrical appliances, a large number of electric wires need to be routed inside. These electric wires are generally used in the form of a wire harness. A wire harness is a structure in which a plurality of electric wires are pre-assembled into a form necessary for wiring. After performing necessary branching, attaching a connector to a terminal, etc., various shapes such as a tape shape, a tube shape, a sheet shape, etc. It is formed by winding the protective material around the outer circumference of the wire bundle.

The wire harness routed in the vehicle may generate noise due to contact with the vehicle body or other members in the vehicle due to vibration during traveling. Therefore, the outer periphery of the wire harness may be provided with a cushioning material for suppressing noise due to contact with other members or the like.

JP 2002-161465 A

With the recent spread of EV (Electric Vehicle) technology in the automobile market, the need for quietness in the passenger compartment is increasing. In order to improve the quietness of the passenger compartment, measures should be taken against low-frequency to high-frequency noise such as road noise and wind noise, which were problems with gasoline vehicles, and noise in the high frequency range of 5000 Hz or higher generated by motors. It is necessary to apply. As part of such measures, there are various vehicle designs such as vehicle design that considers noise reduction, sound absorbing material that absorbs noise in a wide sound range from low frequency to high frequency, resin members that have sound insulation performance equivalent to metal parts, etc. A method has been devised.

In the vehicle, a device that generates high heat, such as an engine, is also installed. In the vicinity of such a device, a sound absorbing material made of a material having nonflammability or sufficient flame retardancy is disposed. However, it should be assumed that even a portion that does not normally reach a high temperature in the engine room is temporarily exposed to an abnormally high temperature due to a failure of the radiator. In particular, a sound absorbing material made of a nonwoven fabric has a sound absorbing characteristic due to a fiber structure including a large amount of voids, and therefore has a drawback that it tends to spread easily when ignited. Therefore, the sound absorbing material mounted in the vehicle is not limited to the one disposed near the device that generates high heat, and it is necessary to consider the flame retardancy as well as the cost and sound absorbing performance. Usually, when using a sound absorbing material made of flammable fibers, flame retardant fibers are added to the nonwoven fabric constituting the sound absorbing material, or flame retardant is applied to the surface to impart flame retardancy. Such processing may reduce the sound absorbing performance of the sound absorbing material. Thus, the sound-absorbing material made of combustible fiber has a problem that it is difficult to maintain both its sound-absorbing performance and impart flame retardancy.

In view of the above problems, the problem to be solved by the present invention is that the sound absorbing material in which the nonwoven fabric is laminated, even when the nonwoven fabric is made of flammable fibers, maintains its sound absorbing performance and imparts flame retardancy. It is to provide a sound absorbing material having a structure capable of coexisting with a wire harness and a wire harness with a sound absorbing material in which the sound absorbing material is integrated with a wire harness.

In order to solve the above problems, a sound absorbing material according to the present invention is a sound absorbing material in which a base material made of a nonwoven fabric and a skin material made of a nonwoven fabric having a thickness smaller than that of the base material are laminated. The gist is that a flame retardant material composed of a nonwoven fabric having a higher density than the base material and the skin material is disposed between the skin material and the skin material.

In the sound absorbing material, the air permeability of the laminate of the base material, the skin material, and the flame retardant material is preferably 5 to 50 cm ³ / cm ² · s.

In the sound absorbing material, the density of the flame retardant is preferably less than 0.3 g / cm ^3.

The sound absorbing material may have a configuration in which at least one skin material is laminated between a plurality of the base materials.

In order to solve the above-described problem, the sound absorbing material-equipped wire harness according to the present invention is such that at least a part of the wire harness in the axial direction is covered with the sound absorbing material so that the sound absorbing material and the wire harness are integrated. It is a summary.

According to the sound-absorbing material and the sound-absorbing material-equipped wire harness according to the present invention, with respect to the sound-absorbing material in which the nonwoven fabric is laminated, even if the nonwoven fabric is made of flammable fibers, its sound-absorbing performance is maintained and flame-retardant It is possible to provide a sound absorbing material having a structure capable of achieving both application and a wire harness with a sound absorbing material in which the sound absorbing material is integrated with a wire harness.

It is the external appearance perspective view and sectional drawing of a sound-absorbing material. It is an external appearance perspective view of other embodiment of a sound-absorbing material. It is an external appearance perspective view of a wire harness with a sound-absorbing material. It is explanatory drawing of the measuring apparatus of a reverberation room method sound absorption coefficient test. It is a graph which shows the test result of a reverberation room method sound absorption coefficient test.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1A is an external perspective view showing an example of a sound absorbing material in the present invention, and FIG. 1B is a cross-sectional view taken along line AA of the sound absorbing material 1 in FIG. The sound-absorbing material and the wire harness with the sound-absorbing material of the present invention can be suitably used as a sound-absorbing material for a vehicle such as an automobile. The noise which intrudes into the passenger compartment from the etc. is cut off.

The sound-absorbing material 1 in this embodiment is a non-woven fabric laminate composed of a base material 21, a skin material 22, and a flame retardant material 3, all of which are made of non-woven fabric. The base material 21 and the skin material 22 are stacked in the thickness direction, and the flame retardant 3 is stacked therebetween. The skin material 22 is made of a nonwoven fabric having a smaller basis weight and thickness than the base material 21, and the flame retardant 3 is made of a nonwoven fabric having a higher density than the skin material 22 and the base material 21. In the sound-absorbing material 1 shown in FIG. 1, the skin material 22 and the flame-retardant material 3 are drawn slightly thicker than actual in order to make it easy to distinguish each layer. The same applies to FIGS. 2 and 3.

From the result of the test conducted by the inventor, the flame retardant 3 having a higher density of constituent fibers than the base material 21 and the skin material 22 is disposed between the base material 21 and the skin material 22. Even when ignited, the fire spread was delayed in the layer of the flame retardant 3 and the effect of improving the flame retardancy of the sound absorbing material 1 as a whole was recognized. The term “flame retardant” as used in the present invention refers to the difficulty of spreading fire, which is a general term for properties that prevent the propagation of flames including slow flame retardance and self-extinguishing properties.

The sound absorbing material 1 is adjusted so that the air flow rate is in the range of 5 to 50 cm ³ / cm ² · s in order to optimize the sound absorbing performance. The “aeration amount” in the present invention means a value measured by the 8.26.1A “Fragile-type air permeability test” method of JIS L 1096 “Fabric and knitted fabric test method”. The fragile type air permeability test can be measured using a commercially available fragile type tester.

Since the sound absorbing material 1 has a structure that improves the flame retardance by further disposing the flame retardant material 3 between the base material 21 and the skin material 22, the base material 21 and the skin material 22 are combustible. It is possible to impart flame retardancy to the sound-absorbing material 1 separately even when a natural fiber is used. In addition, this structure reduces the requirement of flame retardancy for the base material 21 and the skin material 22 itself, and increases the degree of freedom of fibers that can be used for the base material 21 and the skin material 22. It becomes easy to satisfy. Furthermore, since it is not necessary to apply a flame retardant to the surface of the sound absorbing material 1, the sound absorbing performance of the sound absorbing material 1 is not impaired by the flame retardant.

The flame retardant 3 is a 0.2 mm thin-film nonwoven fabric, which itself has a function as a heat-fusible sheet. The base material 21 and the skin material 22 are integrated as the sound absorbing material 1 by being bonded to the flame retardant material 3 which is a heat-fusible sheet. The flame retardant 3 is not necessarily a heat-fusible sheet, and the base material 21, the skin material 22 and the flame retardant 3 are integrated by other means such as a needle punch or a stapler. May be. In the present embodiment, the flame retardant 3 is a thin-film nonwoven fabric for the purpose of providing the flame retardant 3 with a function as a heat-fusible sheet. In this case, the flame retardant 3 can be made thick.

The substrate 21 preferably has a basis weight of 100 to 1000 g / m ² and a thickness of 1.0 to 50.0 mm. When the basis weight increases, the sound absorption coefficient in all frequency bands increases, and when the basis weight decreases, the sound absorption coefficient in all frequency bands tends to decrease. Further, when the thickness is increased, the sound absorption performance in the low frequency band is increased, and when the thickness is decreased, the sound absorption characteristic in the high frequency band tends to be increased. The thickness of the base material 21 can be appropriately adjusted according to the frequency band to be absorbed.

The skin material 22 preferably has a basis weight of 10 to 400 g / m ² and a thickness of 0.1 to 4.0 mm. By making the thickness of the skin material 22 smaller than that of the base material 21, the skin material 22 has higher sound absorption characteristics in the high frequency region than the base material 21, and can absorb noise in a wide frequency band. However, if the basis weight and thickness are smaller than the above ranges, the sound absorbing effect as the sound absorbing material of the skin material 22 may not be sufficiently exhibited.

The basis weight and thickness of the flame retardant 3 are such that the density ρ calculated by the following equation (1) is greater than the density of the base material 21 and the skin material 22 and less than 0.3 g / cm ^3. Molded. The “density” in the present invention means the density ρ calculated by the equation (1).
ρ = (W / 100 ² ) × (10 / T) (1)
ρ: Density (g / cm ³ )
W: Mass per unit area (unit weight) measured according to JIS L 1913 (g / m ² )
T: thickness of the nonwoven fabric under a load of 0.1 kPa (mm)

The above is a preferable configuration of the sound absorbing material 1 only, and if the flame retardant material 3 having a higher density than the nonwoven fabric is disposed between the skin material 22 and the base material 21, the flame resistance of the sound absorbing material 1 is improved. The effect is recognized. In addition, the sound absorbing material 1 is not necessarily used in a configuration in which the skin material 22 and the base material 21 are stacked one by one, and the skin material 22 is laminated between the two base materials 21 as shown in FIG. You may use by the structure made. Further, the lamination position of the skin material 22 is not necessarily the outermost layer (skin).

Examples of the fiber material that can be used for the base material 21 and the skin material 22 include polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyolefin, nylon, polyamide, polyvinyl chloride, rayon, acrylic, acrylonitrile, cellulose, and kenaf.

As the fiber material of the flame retardant 3, it is desirable to use olefin, polyester and polyamide fibers. By using a fiber material having high flame retardancy for the flame retardant 3, it is possible to effectively improve the flame retardance of the sound absorbing material 1 as a whole.

The fiber diameter of the base material 21 is desirably within the range of 4 to 100 μm, and the fiber diameter of the skin material 22 is desirably within the range of 1 to 50 μm. The thinner the fiber diameter, the higher the sound absorbing performance as a nonwoven fabric. However, if the fiber diameter is too thin, the nonwoven fabric may become brittle.

Moreover, as a manufacturing method of the base material 21 and the skin material 22, a spunbond method, a spunlace method, a needle punch method, a melt blown method, or the like can be used.

Although the fiber diameter and manufacturing method of the flame retardant 3 are not particularly limited, the fiber structure should not impair the sound absorption performance of the base material 21 and the skin material 22.

The cross-sectional shape of the fibers of the base material 21, the skin material 22, and the flame retardant material 3 is not particularly limited, and the core-sheath type, cylindrical type, hollow type, side-by-side type, and atypical cross-section fiber having a different shape from normal fibers May be used.

FIG. 3 is an external perspective view showing a wire harness with a sound absorbing material. The wire harness 5 with the sound absorbing material in FIG. 3A is integrated in a state where a part of the wire harness 4 in the axial direction is sandwiched between the two sound absorbing materials 1, and the wire harness 5 in FIG. The wire harness 6 with the sound absorbing material is integrated by winding a part of the wire harness 4 in the axial direction around the sound absorbing material 1. The end portions of these sound absorbing materials 1 are overlapped in the thickness direction, and the overlapped portions are fixed to the wire harness 4 by being connected by a stapler, an adhesive, a tag pin, or the like.

Examples of the wire harness 4 include a bundle of a plurality of electric wires whose core wire is covered with an insulator, and a wire harness 4 that is composed of only one electric wire.

The sound absorbing material 1 covers not only a part of the wire harness 4 but also serves as a sound absorbing material as well as a function as a cushioning material for the wire harness 4.

Below, the method of each test carried out on the sound-absorbing material of the present invention and the results are shown.

[Flammability test and air flow measurement]
The specifications of the base material, the skin material, and the flame retardant used for the flammability test and the air flow rate measurement are as follows. As the sound absorbing material of each example and comparative example, those obtained by laminating only base materials and skin materials having the following specifications and those obtained by laminating flame retardant materials between them were used. In addition, the flame-retardant material used in this example and comparative example also has a function as a heat-fusible sheet, and among each of the examples and comparative examples, the base material of the sound-absorbing material having the flame-retardant material and The skin material is bonded with a flame retardant material. On the other hand, the base material and the skin material of the sound absorbing material that do not have a flame retardant material are integrated by needle punching.
〔Base material〕
Fiber material: Mixed fiber of polyester fiber and low melting point polyester fiber Fiber diameter: φ14 μm
Basis weight: 300 g / m ² or 500 g / m ²
Thickness: 10mm
Manufacturing method: Needle punch (skin material)
Fiber material: Olefin fiber Fiber diameter: φ9μm
Per unit weight: 50 g / m ²
Thickness: 1mm
Manufacturing method: Spunbond (Flame Retardant)
Fiber material: polyester fiber, polyolefin fiber, or polyamide fiber basis weight: 30 g / m ²
Thickness: 0.1-1mm

The specific laminated structure and specifications of the sound absorbing material used in each example and comparative example are shown below. The parentheses in the flame retardant material mean the fiber material and thickness of the flame retardant material, and the parentheses in the base material mean the basis weight of the base material.
Example 1: Skin material / flame retardant material (polyester fiber; 0.2 mm) / base material (300 g / m ² )
Example 2: Skin material / flame retardant (polyolefin fiber; 0.2 mm) / base material (300 g / m ² )
Example 3: Skin material / flame retardant material (polyamide fiber; 0.2 mm) / base material (300 g / m ² )
Example 4: Skin material / flame retardant material (polyester fiber; 0.2 mm) / base material (500 g / m ² )
Example 5: skin material / flame retardant material (polyester fiber; 0.5 mm) / base material (300 g / m ² )
Comparative Example 1: Skin material / base material (300 g / m ² )
Comparative Example 2: Skin material / base material (500 g / m ² )
Comparative Example 3: Skin material / base material (300 g / m ² ) / skin material / base material (300 g / m ² )
Comparative Example 4: Skin material / flame retardant (polyester fiber; 1 mm) / base material (300 g / m ² )
Comparative Example 5: Skin material / flame retardant material (polyester fiber; 0.1 mm) / base material (300 g / m ² )

The flammability test was conducted in accordance with the test method of JIS D 1201, “Tractor / Mechanical Equipment for Automobiles and Agricultural Forests—Flammability Test Method for Interior Materials”. The burning rate was calculated by the following equation (2), and the unit was mm / min. As a result of the test, a sound absorbing material having a burning rate of 50 mm / min or less was evaluated as “◯”, and a material having a larger value was evaluated as “×”.
B = (s / t) × 60 (2)
B: Burning speed (mm / min)
s: Combustion distance (mm)
t: Combustion time (seconds)

The air flow rate was measured by the fragile-type air permeability test method of JIS L 1096. For the measurement, two sound absorbing materials of each Example and Comparative Example were used. The results of the above tests are shown in Table 1. Note that the burning rate of Comparative Example 5 was set to “0” because it did not reach the measurement point.

[Sound absorption performance test]
In order to evaluate the sound absorption performance according to the air flow rate of the sound absorbing material, the reverberation chamber method sound absorption rate was measured using the following test specimens. Table 2 and FIG. 4 show the measurement results.
[Specimen]
Laminate structure: skin material / flame retardant material / base material / skin material / flame retardant material / base material air flow rate: 5, 27, 50, ² , and 58 cm ³ / cm ² · s

The sound absorption coefficient test was performed in accordance with JIS A 1409 “Measurement method of sound absorption coefficient of reverberation chamber method”, and the sound absorption coefficient was obtained by the calculation formula shown in the following equation (3). In the test, as shown in FIG. 5, a speaker 93 connected through a power amplifier 92 to a personal computer 90 through an audio interface 91 and a microphone 95 connected through a microphone amplifier 94 are arranged at predetermined positions. The reverberation chamber 96 is used. In the measurement, first, in a state where the sample 97 (each specimen) was not placed in the reverberation chamber 96, an electrical noise sound was emitted from the speaker 93, the sound was stopped, and the sound attenuation process was measured with the microphone 95. Next, the time over which the sound attenuated in the range of −5 to −35 dB was determined from the measured attenuation curve as the reverberation time 減衰 1. The measurement was performed every 1/3 octave band with a center frequency of 400 Hz to 5000 Hz. Next, a 1 m ² sample 97 was placed on the floor of the reverberation chamber 96, the reverberation time Τ2 was obtained in the same manner as described above, and the sound absorption coefficient (αS) was calculated by the following equation (3). In addition, the value of a sound absorption factor means that a sound is absorbed well, so that it is large.

αS (Sound Absorption Rate) = A / S (3)
S: Area of sample (m ² )
A: Equivalent sound absorption area (m ² ), determined by the following equation (4).
A = 55.3V / c · [1 / Τ2-1 / Τ1] (4)
V: Volume of reverberation chamber without sample (m ³ )
c: Speed of sound in air (m / s)
Note 1: Reverberation time in the reverberation room without sample (s)
Note 2: Reverberation time in the reverberation room with the sample placed (s)

[Test results]
From the results of the sound absorption performance test in Table 2 and FIG. 5, the sound absorbing material has high sound absorption over a wide sound range from low frequency to high frequency when the air flow rate is 5 to 50 cm ³ / cm ² · s (test body 1 to 3). It was confirmed to show performance. Further, when the air flow rate is less than 5 cm ³ / cm ² · s (test body 4), the sound absorption performance in the high frequency region is lowered, and when the air flow rate exceeds 50 cm ³ / cm ² · s (test body 5), It was confirmed that the sound absorption performance in the frequency range deteriorated. From these results, in order to optimize the sound absorbing performance of the sound absorbing material, it is considered more desirable to adjust the air flow rate with 5 to 50 cm ³ / cm ² · s as a guide.

Next, looking at the results of the flammability test in Table 1, a sound absorbing material in which a flame retardant having a higher density than those of the base material and the skin material was stacked between the base material and the skin material (Examples 1 to 6). ), The burning rate was reduced to half or less compared to the case where only the base material and the skin material were laminated (Comparative Examples 1 to 3), and an effect of improving flame retardancy was recognized. Even in the sound absorbing material (Comparative Example 4) in which a flame retardant having a lower density than the skin material was used, an effect of improving the flame retardance was recognized to some extent, but to the extent required by the present invention (burning rate: 50 mm / min) The following) was not reached.

Of the sound-absorbing materials of Examples 1, 5, and 6 that have the same conditions other than the density, the combustion rate is 25 mm in Example 1 (combustion rate: 5 mm / min) and Example 5 (combustion rate: 30 mm / min). There is an opening of / min. From this, it is estimated that the flame retardancy is relatively greatly improved until the density reaches at least about 0.1 g / cm ³ . Therefore, it is considered that the density of the flame retardant is more preferably 0.1 g / cm ³ or more.

On the other hand, Example 6 provided with a flame retardant having a density of 0.3 g / cm ³ uses a material other than polyester fiber because the combustion rate is further reduced as compared with the sound absorbing material of Example 1 (Example) It is predicted that the combustion rate can be further reduced by increasing the density of the flame retardant, including 2 and 3). However, since the sound absorbing material of Example 6 has an air flow rate of 3 cm ³ / cm ² · s, it is slightly deviated from the above-described preferable range of the air flow rate (5 to 50 cm 3 / cm 2 · s). Therefore, it is considered that the density of the flame retardant is more preferably less than 0.3 g / cm ³ .

The embodiments, examples, and comparative examples of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments and the like, and various modifications can be made without departing from the spirit of the present invention. Modification is possible.

Claims

A sound absorbing material in which a base material made of a non-woven fabric and a skin material made of a non-woven fabric having a thickness smaller than the base material are laminated,
A sound-absorbing material, wherein a flame-retardant material made of a non-woven fabric having a higher density than the base material and the skin material is disposed between the base material and the skin material.
The sound-absorbing material according to claim 1, wherein an olefin-based, polyester-based, or polyamide-based resin is used as the flame retardant material.
The sound absorbing material according to claim 1 or 2, wherein an air permeability of the laminate of the base material, the skin material, and the flame retardant material is 5 to 50 cm 3 / cm 2 · s.
The sound absorbing material according to any one of claims 1 to 3, wherein the flame retardant material has a density of less than 0.3 g / cm 3 .
5. The sound absorbing material according to claim 1, wherein at least one skin material is laminated between a plurality of the base materials.
The sound absorbing material and the wire harness are integrated by covering at least a part of the wire harness in the axial direction with the sound absorbing material according to any one of claims 1 to 5. Wire harness with sound absorbing material.